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Basics of liver function and physiology
Liver anatomy The liver is comprised of''' two large sections', the right and left lobes, which consist of thousands of lobules. These lobes receive blood from two sources; oxygenated blood from the hepatic artery, and nutrient-rich blood from the hepatic portal vein. The two lobes of the liver are connected to small ducts that connect to larger ducts forming the hepatic duct; transports bile produced by liver cells to the gallbladder and duodenum. Liver functions The liver is responsible for '''filtering and regulating most chemical levels in the blood', entering from the stomach and intestines, before passing through the rest of the body. Through the filtration process, the liver breaks down drugs and nutrients for later absorption, and converts excess glucose into glycogen for storage. The liver is also responsible for the regulation of blood clotting and the blood levels of amino acids, and''' storing iron processed from the hemoglobin. The bile excreted by the liver h'''elps carry away waste, '''and breaks down fat molecules for easier absorption and digestion. The liver also '''converts ammonia to urea, which is excreted through urine. Once a harmful substance has broken down, they are excreted into the bile or blood; bile by-products excrete through feces, and blood-by-products excrete through urine. Other functions of the liver include production of cholesterol, major plasma proteins, carrier proteins, apoliproproteins, hormones, and prohormones. ''' In order to have a more complete idea of the liver anatomy as well as functions, you can watch the video below which explains in a simple way what was mentioned above. Mr Henderson's case ''Liver function can be assessed by the measurement of enzyme and protein biomarkers',''' such as aspartate transaminase (AST), alanine transaminase (ALT) and bilirubin. Accumulation of such toxic substances can indicate inadequate functioning of the liver to break down and remove these substances from the body via bile, possibly due to liver damage or disease. In addition, enzymes such as alkaline pshosphatase and γ-glutamyl transpeptidase '''may be used as a marker for high alcohol intakes which can contribute towards liver damage, but also to identify any possible damage in bile canaliculi, which may prevent adequate bile secretion. '''The hepatocyte function is measured by protein levels in the blood, such as albumin, but also by measuring'prothrombin' (blood clotting) time, low levels of which also indicate liver damage. Hypoalbuminia can result in substances which are normally albumin bound e.g. drugs, to be free in the plasma, which can result in rapid hepatic metabolism. Hepatocyte metabolism can be measured by an aminopyrine test, levels of ammonia and also galactose elimination. Discussion of the case given The table with Mr Henderson's liver function test are provided below: Elevated levels of total bilirrubin, AST, ALT, alkaline phosphatase and γ-GT, as in the case of Mr. Henderson, indicates hepatic failure. Low albumin levels and prothrombin time also indicates hepatic failure to metabolise/synthesise adequate levels of proteins. The hepatic failure could be acute (e.g. hepatitis) or chronic (e.g. cirrhosis). Liver scarring, as seen in the patient, can cause veins of esophagus to enlarge. This may in turn lead to esophageal varices, in which the blood flowing through the veins increases, causing a huge tension on the walls of veins, resulting in hemorrhage. While, esophegael varices have not been diagnosed in the patient, he may be at risk. Evidence has shown that varices can disappear in alcohol cessation. Therefore alcohol intake in the patient should be monitored or completely stopped. It should also be considered that information regarding Mr Henderson’s health status, including dietary/lifestyle habits e.g. alcohol intake, past medical history e.g. obesity, hypertension, diabetes mellitus, and use of medication are unknown at this stage. While interventions such as altering medication doses and protein intake, may assist with reducing toxicity build up in the body, more information would be necessary before treating Mr Henderson for acute/chronic hepatic failure. An accute diagramm of the discussion which was made as well as some possible scenarios of Mr Henderson's case, are shown in the next image.